The present invention relates generally to a mail or document stacking machine and, more particularly, to a stack support for providing a resisting force to the stack as the mailpiece or document is accumulated into the stack.
In a typical mail-handling machine, mailpieces are sorted and pushed into a plurality of stacking bins where the mailpieces are accumulated in substantially vertical stacks. In each stacking bin, a paddle, or an abutment member, is used to support the stack while allowing the stack thickness to increase. In order to providing sufficient support to the growing stack, a resisting force is usually provided to the paddle against the stack. As disclosed in U.S. Pat. No. 5,429,249 (Belec et al.), the paddle 40 is slidably mounted on a shaft or bar 32 by means of a cylindrical shaped member 34. The cylindrical shaped member 34 is spring-loaded to provide a resisting force 150 to the paddle 40 as the stack 100 is pushed in a direction 102 when the mailpiece 110 is accumulated into the stack 100 by an input mechanism 90, as shown in FIG. 1. As disclosed in U.S. Pat. No. 4,524,965 (Kulpa), one end of a cord 54 is tied to the cylindrical shaped member 34 and the other end of the cord 54 is wrapped around a rotary displacement device 60. As the cylindrical member 34, along with the paddle 40 and the stack 100, is pushed along the direction 102, it causes the rotary displacement device 60 to rotate along a rotation direction 106, as shown in FIG. 2. A pulley 70 is fixedly mounted on the rotary displacement device 60 for motion. One end of another cord 52 is wrapped around the pulley 70 and the other end of the cord 52 is tied to a spring 50. When the rotary displacement device 60 is rotated along the rotation direction 106, it causes the spring 50 is stretched along the direction 104. As the spring 50 is stretched, it increases the tension 202 in the cord 52, thereby increasing the resistance force 150 provided to the paddle 40.
While the resisting force providing systems, as disclosed in Belec et al. and in Kulpa, are useful in supporting a stack of mailpieces as the thickness of the stack increases, the resisting force cannot be adjusted according to the load of the mailpieces. On the one hand, if the resistance force is too high, then lightweight mailpieces may be damaged when they are accumulated into the stack. On the other hand, if the resistance force is too low, the stack may overpower the paddle and cause the entire stack to topple over.
It is advantageous and desirable to provide a stack urging force system wherein the resistance force provided to the paddle is adjustable according to the load of the mailpieces.
According to first aspect of the present invention, a paddle urging system for use in a stacking bin having a first end and an opposing second end, wherein a paddle is provided in the stacking bin to support a stack of mailpieces in the stacking bin and wherein the mailpieces are accumulated into the stack at the first end of the stacking bin, thereby increasing the thickness of the stack and pushing the stack against the paddle in a first direction toward the second end of the stacking bin, said paddle system comprising:
an urging mechanism, operatively connected to the paddle, for providing an urging force to urge the paddle to move in a second direction opposite from the first direction while supporting the stack; and
an adjustable resisting force mechanism, operatively connected to the urging mechanism, for providing a resisting force to the paddle against the pushing of the stack toward the second end when the mailpieces are accumulated into the stack, in addition to the urging force provided by the urging mechanism.
According to the present invention, wherein the urging mechanism comprises a spring, connected to the paddle by a flexible member, for providing the urging force to the paddle.
According to the present invention, the adjustable resisting force mechanism comprises a clutch system for providing the resisting force, and the flexible member is mechanically engaged with the clutch system for conveying the resisting force provided by the clutch to the paddle.
According to the present invention, the clutch system comprises a pulley engaged with a one-way clutch such that the pulley is allowed to turn in a first rotation direction with respect to a rotation axis and the pulley is prevented from turning in a second rotation direction opposite from the first rotation direction, and wherein the one-way clutch is further engaged with a rotating member with an adjustable friction force and the rotating member is disposed axially with the rotation axis, such that when the pulley is caused to turn in the second rotation direction by the pushing of the stack toward the second end of the stacking bin, the one-way clutch causes the rotating member to rotate against the friction force for providing the resisting force to the flexible member, and when the pulley is caused to turn in the first rotation direction, the one-way clutch and the rotating member are effectively disengaged from the pulley.
According to the second aspect of the present invention, a stacking bin for use in a mail processing machine for accumulating mailpieces into a stack from a first end of the stack, wherein the stack is pushed toward a first direction when the mailpieces are accumulated into the stack, thereby increase the thickness of the stack and pushing the stack along a first direction, said stacking bin comprising:
a paddle, provided at the second end of the stack opposite from the first end, for supporting the stack,
an urging mechanism, operatively connected to the paddle, for providing an urging force to urge the paddle to move against the stack toward a second direction opposite from the first direction; and
an adjustable resisting force mechanism, operatively connected to the urging mechanism, for providing a resisting force to the paddle against the pushing of the stack when the mailpieces are accumulated into the stack, in addition to the urging force provided by the urging mechanism.
The present invention will become apparent upon reading the description taken in conjunction with FIGS. 1 to 4.